There was an interesting BBC show the other day about plastic waste and they were pointing out that buying loose vegetables in major supermarkets was between 20-50% more expensive than buying them prepackaged.
I think I easily save 20-50% when I buy the amount I can eat before it goes bad instead of having to buy a larger amount because it's prepackaged in a too-big-for-me package.
Come to think of it, I never throw out stuff like fruit which I buy "per piece" instead of prepackaged, where as carrots which usually only comes prepackaged where I shop is something I often have to throw out of because the last ones have gone bad before I got to them. This have meant I rarely eat carrots anymore and instead buy something else that isn't prepackaged.
Same thing with bread actually. But then they started selling smaller breads all over the country to combat food waste, and it really has, I don't remember throwing out bread in the last couple of years.
For the consumer. I really doubt that the supermarket pays a different price by getting them in big boxes rather than plastic bags. If they do, it's probably less. :)
Carrots and all root veg will easily keep for a couple of months or so if you store them in the fridge. Make sure they're completely dry, don't wash - they keep better - and remove any sprouting tops, then keep in an air tight box or bag, or as second best, just in the non-ventilated drawer of the fridge.
Or about as long in sand if you have a cool dry cellar or garage to serve as makeshift root cellar. Store flat in plastic trays or tubs covered with dry horticultural sand or soil.
I'm not sure why? It's standard practice in UK supermarkets, although prepacked bags are also available.